ABSTRACT
Combination of monoammonium glycyrrhizinate and cysteine hydrochloride (MG-CH) has been used in the treatment of chronic liver disease for decades, however, its mechanism is still unclear. Our previous studies showed that MG-CH confers the optimal therapeutic effect at the ratio of 2:1 to against acute liver damage. In this study, it was used to investigate the anti-fibrotic effect induced by CCl4. The results showed that injection of MG-CH produced anti-fibrotic effect ranged from 30 mg/kg to 60 mg/kg, evidenced by decreased the collagens deposition and inhibited the production of hydroxyproline. Mechanism study found that Nrf2/ARE signaling pathway was activated by MG-CH, whereas loss of hepatocytic Nrf2 abolished its anti-fibrotic effect significantly. Furthermore, it was demonstrated that MG-CH is a non-canonical NRF2 inducer, which promoted the autophagy activity and release the Nrf2 from keap 1 by promoting the phosphorylation of p62 at Ser351. Knockdown of p62 abolished the enhancement of nuclear accumulation of Nrf2 by MG-CH. All of these results suggested that up-regulation of Nrf2/P62/Keap1 involves in the anti-fibrotic effect of MG-CH, which provide a rational explanation for the usage of MG-CH in the treatment of fibrosis.
Subject(s)
Antifibrotic Agents/pharmacology , Cysteine/pharmacology , Glycyrrhizic Acid/pharmacology , Liver Cirrhosis/drug therapy , Animals , Antifibrotic Agents/therapeutic use , Carbon Tetrachloride/administration & dosage , Carbon Tetrachloride/toxicity , Cysteine/therapeutic use , Disease Models, Animal , Gene Knockdown Techniques , Gene Knockout Techniques , Glycyrrhizic Acid/therapeutic use , Hep G2 Cells , Hepatocytes , Humans , Kelch-Like ECH-Associated Protein 1/metabolism , Liver Cirrhosis/chemically induced , Liver Cirrhosis/pathology , Male , NF-E2-Related Factor 2/genetics , NF-E2-Related Factor 2/metabolism , Oxidative Stress/drug effects , Rats , Sequestosome-1 Protein/genetics , Sequestosome-1 Protein/metabolism , Signal Transduction/drug effects , Up-Regulation/drug effectsABSTRACT
Combination of monoammonium glycyrrhizinate and cysteine hydrochloride (MG-CH) has been used for treatment of chronic liver damage in clinic for several years, however, the effect of MG-CH on acute liver injury (ALI) is still obscure. In this study, we aimed to investigate the effect of MG-CH on ALI induced by co-injection of lipopolysaccharide (LPS) and d-galactosamine (GalN). Our results found that MG-CH produced the optimal therapeutic effect at the ratio of 2:1, as manifested by the increased survival percentage, decreased ALT and AST level and improved hepatic pathology. Both oxidative stress and inflammation induced by LPS/GalN were attenuated by MG-CH. Mechanism study showed that MG-CH promoted the nuclear accumulation of Nrf2 and its transcriptional activity, as well as improved Nrf2-target genes' expression. It was also found that activation of Nrf2 is dependent on the MG, not CH. Blockade of Nrf2 abolished the anti-inflammatory effect of MG-CHinduced by LPS/GalN, while inhibition of NFκB showed no effect on its anti-oxidative effect, though the inhibited phosphorylation of IκB and NFκB were detected in liver. The protective effect of MG-CH against ALI was abolished in Nrf2-/- mice. All of these results suggested that MG-CH ameliorated LPS/GalN induced ALI through Nrf2/ARE pathway.
Subject(s)
Chemical and Drug Induced Liver Injury/drug therapy , Cysteine/therapeutic use , Glycyrrhizic Acid/therapeutic use , NF-E2-Related Factor 2/metabolism , Animals , Antioxidant Response Elements , Cells, Cultured , Chemical and Drug Induced Liver Injury/genetics , Chemical and Drug Induced Liver Injury/metabolism , Cysteine/pharmacology , Cytokines/genetics , Drug Combinations , Galactosamine , Glutathione/metabolism , Glycyrrhizic Acid/pharmacology , Heme Oxygenase-1/genetics , Hepatocytes/drug effects , Hepatocytes/metabolism , Lipopolysaccharides , Liver/drug effects , Liver/metabolism , Male , Malondialdehyde/metabolism , Mice, Inbred C57BL , Mice, Knockout , NF-E2-Related Factor 2/genetics , Peroxidase/metabolism , Signal Transduction/drug effects , Superoxide Dismutase/metabolismABSTRACT
The mechanism of demyelinating diseases is controversial, while demyelination and remyeliantion disorder is the acknowledged etiology and therapeutic target. Untill now, there is no efficient therapy for these diseases. CZ-7, a new derivative of Claulansine F, which has been reported before, were investigated its pro-remyelination effect and its associated mechanism in cuprizone (CPZ)-induced demyelination model. In this study, male C57BL/6 mice were subjected to CPZ (300 mg/kg) through intragastric gavage and were orally administered CZ-7 (20 mg/kg) meanwhile. The results of weight monitoring and behavioral testing showed that CZ-7 can significantly improve behavior dysfunction in the demyelinating mice. Luxol-fast blue (LFB) staining, myelin basic protein (MBP) immunostaining, transmission electron microscopy (TEM) and QPCR results indicated the therapeutic effect of CZ-7 on CPZ mice model. Furthermore, degraded myelin basic protein (dMBP) immunofluorescent staining and oil red O staining showed that CZ-7 contributed to the clearance of degraded myelin debris. More microglia displayed phagocytic shape assembled in corpus callosum (CC) and there was an active process of phagocytosis in microglia after CZ-7 treatment. Immunofluorescent staining and QPCR analysis revealed the M2-polarized phenotype switch of microglia in the process of myelin debris removel, which demostrated the microenvironment improvement of CZ-7. Moreover, immunofluorescent staining of NG2 and O4 demonstated that more oligodendrocyte precursor cells (OPCs) existed in CC after CZ-7 treatment. In conclusion, our results demonstrated CZ-7 has a potential therapeutic effect for MS and other demyelinating diseases through enhancing myelin debris clearance to improve the microenvironment.
